Genetic Code

Mitosis - animation

• If you look at the onion root under a microscope, you can see cells of different shapes and sizes, such as cells with an apparent nucleus, cells that appear to be split into two cells, and cells that have no nucleus and that have structures that look like short strings or rods.

• Structures that look like short strings or rods in cells are called chromosomes, which appear when cell division occurs. Therefore, by observing the shape and movement of chromosomes, you can distinguish the process of cell division.

• Chromosomes are loosened like thin threads when cells don’t divide (DNA). Before the cells divide, the DNA is replicated and thickened, shortened together. In Prophase and Metaphase, one chromosome consists of two strands called chromatid, each with the same genetic information. (Replicated)

Meiosis - animation

• Meiosis is a type of cell division that results in four daughter cells in reproductive organs. Each daughter cells have half the number of chromosomes of the parent cell,

• In meiosis, the DNA is duplicated and followed by two consecutive divisions. This reduces the number of chromosomes from diploid(2n) to haploid (n).

Asexual Reproduction and Sexual Reproduction - animation

• Asexual reproduction
  Some living things do not make reproductive cells. They make new offspring through cell division. This method of reproduction without male and female reproductive cells is called asexual reproduction.

• Sexual reproduction
  Many of the creatures around us can divide males and females. In these organisms, females and males make reproductive cells through meiosis, and reproductive cells fertilize them to produce offspring.

• Advantages of sexual reproduction over asexual reproduction
  In asexual reproduction, offspring with the same traits as their parents continue to appear. On the other hand, in the case of sexual reproduction, since various offspring appear during reproduction, some individuals can adapt to sudden environmental changes.